The invention relates to an apparatus for tempering the surfaces of mutually displaced cams of a cast-iron camshaft. More particularly, the invention relates to such an apparatus in which a camshaft may be rotatably mounted with energy sources disposed movably at the periphery of the camshaft at a distance from the cam axis acting against the surfaces of the cams for the preferably punctiform fusing on the surfaces. A master camshaft is rotatably mounted by way of means for synchronously driving the master camshaft and the camshaft to be tempered. Control cams scan the surface of the master cams for the adjustment of the distance of the energy sources from the cam axis. The camshaft is also mounted so as to be movable in its rotational mounting in the direction of the camshaft axis.
In a known apparatus (cf., for example, U.S. Pat. No. 4,147,335) the camshaft is mounted horizontally and the energy sources are shielded arc welding torches which are disposed above a horizontal plane through the rotational axis of the camshaft at a distance from the rotational axis of said camshaft. The torches are controlled by way of gearing by the master camshaft in regard to its distance from the cams in such a way that the distance to the surface of the pertinent cam is constant independently of the shape of the cam. At the same time, it turned out to be effective to dispose the torches around the camshaft axis inclined toward the horizontal plane. The inclination corresponds to about 50.degree. and is to ensure that the liquid metal would not drip off the surface of the cam.
Such apparatuses have the disadvantage that the individual cams, because of the pertinent angular displacement of said cams, may not be fused-on synchronously. Rather, the individual torches are fired by way of cam switches coupled with the drive of the camshafts whenever the area of a cam which has to be tempered enters into the vicinity of the torch. This method of operation also leads to a prolongation of the force stroke, since the individual cams must be fused-on mutually displaced in time.
The invention deals with an improvement of apparatuses of the type designated in more detail above with which a reduction of the force stroke may be achieved. According to the invention, this improvement will be achieved by disposing the camshaft in its support essentially in a perpendicular axial position disposing the energy sources distributed around the longitudinal axis of the camshaft, mutually disposed at angular distances corresponding to the relative angular displacements of the cams. In this arrangement, the cam surfaces of the individual cams can be fused-on in a synchronously running force stroke.